Facebook CEO Mark Zuckerberg and his wife, Priscilla Chan, want to expand their reach beyond their social media empire. Their philanthropic company, which turns four years old Tuesday, is awarding millions of dollars to projects like eliminating all disease, transforming criminal justice and improving equity in education. "CBS This Morning" co-host Gayle King spoke with them at the offices of the Chan Zuckerberg Initiative for their first-ever joint network TV interview about what they want to accomplish.